The present invention relates to a utility vehicle having a drive motor or engine and a shifting claw transmission with an electric motor which can also be operated as a generator.
U.S. Pat. No. 5,560,249 discloses a group transmission with claw clutches in which a power synchronizer which comprises an electric motor is used. The electric motor drives a countershaft via an intermediate gearwheel.
In addition, DE 42 020 83 C2 discloses a different generic type of vehicle transmission with electric drive motor for a hybrid vehicle, a which has a frictionally locking synchronization means and an electric machine. The electric machine can be operatively connected to a countershaft so that the latter can be used as synchronization means for relieving the loading on the frictionally locking synchronization means.
EP 1007383 B1 discloses a drive train for a hybrid vehicle including electric machine mounted to a countershaft of a transmission.
DE 195 30 231 discloses a hybrid drive for a motor vehicle in which an internal combustion engine and an electric motor are used for driving the vehicle. The internal combustion engine and the electric motor act simultaneously or alternately on the drive shaft or the countershaft of a speed-changing transmission which is provided with shiftable gearwheels and with synchronous clutches for shifting a plurality of gear speeds. In order to achieve comfortable gear speed changes, the electric motor can be coupled to the drive shaft via a positively locking clutch. This clutch is released when a gear speed is engaged and subsequently the clutch is closed again. Before the clutch closes, the electric motor is adjusted at least approximately to synchronous running in relation to the drive shaft.
An electric motor with a speed change transmission is also known from DE 198 59 458 A1, which however is of a different generic type.
It is the object of the present invention to provide a cost-effective utility vehicle transmission which provides for comfortable and smooth gear speed changes.